1. Field of the Invention
The field of the invention relates to an improved automatic coal stoker having an enshrouded pusher of variable stroke length and a means to break up or suppress clinker formation.
2. Description of the Prior Art
The prior art is best demonstrated by U.S. Pat. No. 4,537,140 to Baker which has at the bottom of the hopper a reciprocating, sliding plate with a lip at its rear forming a pusher bar, the plate of which tends to vibrate the infed coal and the pusher causing the coal to travel down an inclined fire grate. This configuration has no means, however, for accurate regulation of the amount of coal infed nor to break up or prevent the formation of clinkers. Pusher bars of variable reciprocating stroke are generally known. None, however are designed to keep the bar from contact with the coal or its fines. With wet coal or fines and the gases emitted in the burning thereof, sulfuric and nitric acid are formed which attack the pusher particularly and also cause jamming and excessive wear.